Fix Linker.sInBrowserProcess to avoid false negatives

base/android/java/src/org/chromium/base/library_loader/Linker.java

Index: base/android/java/src/org/chromium/base/library_loader/Linker.java
diff --git a/base/android/java/src/org/chromium/base/library_loader/Linker.java b/base/android/java/src/org/chromium/base/library_loader/Linker.java
index 23f953c24a8c7693209374a90acc87c4eeb1d4be..c7082411ab6cd30dd61344d65370123379a2a932 100644
--- a/base/android/java/src/org/chromium/base/library_loader/Linker.java
+++ b/base/android/java/src/org/chromium/base/library_loader/Linker.java
@@ -106,16 +106,15 @@ import javax.annotation.Nullable;
  *    running any native code from any of the libraries (except their static
  *    constructors, which can't be avoided).
  *
- *  - A service process shall call either initServiceProcess() or
- *    disableSharedRelros() early (i.e. before any loadLibrary() call).
- *    Otherwise, the linker considers that it is running inside the browser
- *    process. This is because various Chromium projects have vastly
- *    different initialization paths.
+ *  - A service process shall call initServiceProcess() early (i.e. before any
+ *    loadLibrary() call). Otherwise, the linker considers that it is running
+ *    inside the browser process. This is because various Chromium projects have
+ *    vastly different initialization paths.
  *
  *    disableSharedRelros() completely disables shared RELROs, and loadLibrary()
  *    will behave exactly like System.loadLibrary().
  *
- *    initServiceProcess(baseLoadAddress) indicates that shared RELROs are to be
+ *    enableSharedRelros(baseLoadAddress) indicates that shared RELROs are to be
  *    used in this process.
  *
  *  - The browser is in charge of deciding where in memory each library should
@@ -197,8 +196,6 @@ public class Linker {
     private static boolean sRelroSharingSupported = false;
 
     // Set to true if this runs in the browser process. Disabled by initServiceProcess().
-    // TODO(petrcermak): This flag can be incorrectly set to false (even though this might run in
-    // the browser process) on low-memory devices.
     private static boolean sInBrowserProcess = true;
 
     // Becomes true to indicate this process needs to wait for a shared RELRO in
@@ -487,7 +484,7 @@ public class Linker {
 
     /**
      * Call this to send a Bundle containing the shared RELRO sections to be
-     * used in this process. If initServiceProcess() was previously called,
+     * used in this process. If enableSharedRelros() was previously called,
      * finishLibraryLoad() will not exit until this method is called in another
      * thread with a non-null value.
      * @param bundle The Bundle instance containing a map of shared RELRO sections
@@ -513,7 +510,7 @@ public class Linker {
         }
         synchronized (Linker.class) {
             // Note that in certain cases, this can be called before
-            // initServiceProcess() in service processes.
+            // enableSharedRelros() in service processes.
             sSharedRelros = clonedBundle;
             // Tell any listener blocked in finishLibraryLoad() about it.
             Linker.class.notifyAll();
@@ -540,35 +537,45 @@ public class Linker {
         }
     }
 
+    /**
+     * Call this method before enabling/disabling shared RELRO sections to
+     * indicate that this is a service process (i.e. not a browser process).
+     */
+    public static void initServiceProcess() {
+        if (DEBUG) Log.i(TAG, "initServiceProcess() called");
+        synchronized (Linker.class) {
+            sInBrowserProcess = false;
+            sBrowserUsesSharedRelro = false;
+        }
+    }
 
     /**
      * Call this method before loading any libraries to indicate that this
-     * process shall neither create or reuse shared RELRO sections.
+     * process shall neither create nor reuse shared RELRO sections.
      */
     public static void disableSharedRelros() {
         if (DEBUG) Log.i(TAG, "disableSharedRelros() called");
         synchronized (Linker.class) {
-            sInBrowserProcess = false;
             sWaitForSharedRelros = false;
-            sBrowserUsesSharedRelro = false;
         }
     }
 
     /**
      * Call this method before loading any libraries to indicate that this
      * process is ready to reuse shared RELRO sections from another one.
-     * Typically used when starting service processes.
+     * Typically used when starting service processes. Any calls to this method
+     * must be preceded by initServiceProcess().
      * @param baseLoadAddress the base library load address to use.
      */
-    public static void initServiceProcess(long baseLoadAddress) {
+    public static void enableSharedRelros(long baseLoadAddress) {
         if (DEBUG) {
             Log.i(TAG, String.format(
-                    Locale.US, "initServiceProcess(0x%x) called", baseLoadAddress));
+                    Locale.US, "enableSharedRelros(0x%x) called", baseLoadAddress));
         }
         synchronized (Linker.class) {
+            assert !sInBrowserProcess;
+            assert !sBrowserUsesSharedRelro;

[rmcilroy, 2015/02/17 17:30:33]

As discussed, maybe we should consider packaging this info up into a enum or
config object, since there are some bools which only make sense for the browser
process, and some which only make sense on the renderer process.

             ensureInitializedLocked();
-            sInBrowserProcess = false;
-            sBrowserUsesSharedRelro = false;
             if (sRelroSharingSupported) {
                 sWaitForSharedRelros = true;
                 sBaseLoadAddress = baseLoadAddress;